<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    div {
       
        /* float: left; */
        width: 300px;
        height: 300px;
        background-color: #000;
        overflow: hidden;
        margin:0 auto ;
    }
    /* div::after {
        content: "";
        display: block;
        width: 300px;
        height: 300px;
        background-color: red;
        transform: rotate(180deg);
        transform-origin: left bottom;
        transition: all .5s;
    }
    div:hover::after {
        transform: rotate(0deg);
       
    } */
</style>
<body>
    <div></div>
    <!-- <div></div>
    <div></div> -->
</body>
</html>